Silent electric switch



1957 H. E. SCHLEICHER 3,354,275

' SILENT ELECTRIC SWITCH Filed Sept. 27, 1965 3 Sheets-Sheet 1 I I /7gL3 INVENTOR O o 8; G Po 0E O Hora/c7 Same/Cher BY h/s of/ome s 0 4 244wNov. 21, 1967 H. E. SCHLEICHER 3,354,275

' SILENT ELECTRIC SWITCH Filed Sept. 27, 1965 5 Sheets-Sheet 2 INVENTOR.

Hora/c7 ESCh/e/Che/ BY his af/omeys United States Patent Ofiice3,354,275 Fatented Nov. 21, 1967 3,354,275 SILENT ELECTREC SW1T CHHarold E. Schleicher, West Hartford, Conn, assignor to The Arrow-Hart &Hegeman Electric ompany, Hartford, Conn, a corporation of ConnecticutFiled Sept. 27, 1965, Ser. No. 49tl,322 Claims. (Q1. 200-68) ABSTRACT OFTHE DKSCIBSURE This invention relates to an electric switch and inparticular to a switch which is of rugged construction, simple andeconomical to manufacture and quiet in operation.

The desirability of switches which are quiet in operation for use inhome and oflice lighting installations, for example, has long beenappreciated and many such devices are currently available. However,previous designs have used over-center coiled springs, and single-actionbumper means, and have been diiiicult and expensive to manufacture orhave had an undesirably short life as well as perceptible noise level.There has thus been a need for a switch which would operate with minimalnoise for an extended period of service. Therefore it is an object ofthe invention to provide such a device.

Another object of the invention is to provide a switch which is quieterin operation and easily adaptable to single pole, double pole or threeway operation.

Another object of the invention is to provide a switch of the classdescribed having a minimal number of parts which may also be assembledin a single operation without machine preassembly.

Another object of the invention is to provide a switch of the classdescribed which is safer than presently avail able designs.

Another object of the invention is to provide a switch of the classdefined in which dielectric shorting is suppressed.

Other objects will become clear from a consideration of the followingspecification and claims.

In accordance with the invention, the enumerated objects and others areattained by means of a switch comprising a hollow casing having at leastone side wall with openings for wire terminals; combined terminal andcontact members seated edgewise in said casing, oneof said membershaving a flexible contact portion engageable with and disengageable fromanother of said members; an operating lever member preferably mounted insaid casing, there being on said operating member (i) cam means engagingsaid flexible portion to cause it to move laterally, for engagement withand disengagement from said other member, the latter being by positiveaction, and (ii) an ogival cam engaging with novel, silently operatingpositioning means. For cooperation with the operating lever, there aredouble-action bumpers on the casing, and a leaf spring and ananti-friction roller, the roller being between the spring and theoperating lever.

The invention will be further described with reference to theaccompanying drawings in which:

FIG. 1 is an exploded view partly cut away of a switch according to theinvention.

FIG. 2 is a bottom plan view of the cover of the switch shown in FIG. 1.

FIG. 3 is a plan view of the bridge shown also in FIG. 1.

FIG. 4 is a plan view of the base of the switch of FIG. 1, the showingbeing of a switch arranged for three- Way operation, with the operatinglever removed.

FIG. 5 is a view in vertical section along the line 55 of FIG. 4, theoperating lever and cover being in position in this view, however.

FIG. 6 is a view in vertical section along the line 6-6 of FIG. 4, theoperating lever and cover again being in position.

FIG. 7 is a view in vertical section along the line 77 of FIG. 4, thecover again being in position but the operating lever being omitted.

FIG. 8 is a View in vertical section of a pin or roller for use in aswitch according to the invention.

FIG. 9 is a perspective view of a movable contact member for use in aswitch according to the invention.

FIG. 10 is a view in elevation of a fixed contact memer according to theinvention.

FIG. 11 is a perspective view of a bumper for use in a switch accordingto the invention.

FIG. 12 is a perspective view of the operating lever shown also in FIGS.1, 3, 4 and 5.

FIG. 13 is a perspective view of another form of operating lever for usein a double or single pole switch.

Fl". 14 is a plan view of a switch base according to the inventionarranged for double pole operation, with the operating lever removed.

Referring to the drawings:

As shown in FIG. 1, a switch according to the invention may comprise abase 113, an operating lever member 11 and a cover 12. The cover 12 maybe secured to the base by any convenient means. In the embodiment shown,the cover is attached to the base by means of a bridge 13 and screws 14which pass through holes 15, 16 in the base and cover respectively andare threaded into tapped holes 17 in the bridge 13.

The embodiment specifically to be described in connection with FIGS.1-12 is arranged for three-way operation. Referring particularly toFIGS. 1 and 5 to 7, the base it comprises in general a floor 13, two endwalls 19 and 29 and two side walls 21 and 22. The side wall 21 has awing 21a extending at its midpoint and two windows 23 and 24 forreceiving the terminal plates 25 and 26 of a fixed contact 27 and amovable contact 28, respectively. As shown more clearly in FIGS. 9 and10, fixed contact 27 comprises a flat terminal plate 25 of copper orlike metal having an car 29 to which may be aflixed a contact button M.A tapped hole 31 is provided in the plate 25 through which a terminalscrew 32 (FIG. 4) may be threaded for afiixing a wire (not shown). Themovable contact 28 comprises terminal plate portion 26 and a flexiblearm portion which hooks around behind the plate 26. The arm portion hasa base section 33a, more or less parallel to the plate portion 26 and.an end section 33/) which is reduced in width compared to the basesection and is normally positioned in a plane between the plane of thebase section and the plane of the terminal plate 26 by a bent section330. The end section 33]) supports a contact button 34. The contact 23is formed of a material, such as bronze, which in the conformationdescribed imparts a substantial degree of springiness to the contactarm. A tapped aperture 35 (FIG. 5) is provided in terminal plate 26 fora terminal screw 36.

The fixed contact 27 is positioned just inside the window 23 in a sidewall 21 by means of a slot 37 (FIG. 5)

3 in the floor 18 of the base just outside of the window 23 into whichslot the terminal plate 25 of the contact fits. A projection 38 isformed arising out of the floor 18 of the base directly behind the slot37 which also aids in retaining the fixed contact in position.

The movable contact 28 is positioned in a similar fashion just behindthe window 24, its terminal plate 26 fit ting into a slot 39 (FIG. 5)and being supported by a projection 40.

The side wall 22, like the wall 21, has two windows 41 and 42. Theterminal plate 43 of a movable contact44, identical to the movablecontact 28, is positioned just inside the window 41 in a slot 45 (FIG.7) supported by a projection 46. A terminal screw 47 is threaded intothe plate 43.

A blind contact 48 is positioned in a slot 49 (FIG. 7) just'inside thewindow 42 and is supported by a projection 50. The contact 48 isidentical with the fixed contact 27 except that it has no terminal screwor threaded hole.

The interior of the base is divided into three compartments 51, 52 and53 by internal walls 54 and 55. The outer compartments 51 and 52 containthe fixed and movable contacts just described. The central compartment53, as can best be seen from FIGS. 4 and 6, has a V- shaped well 56 inits bottom. Two ledges 57 and 58 are formed On either end of the welland a fiat spring 59s is supported on those ledges. Midway along theinside of walls 54 and 55 are vertical channels 59 and 60 in which arepositioned the ends of a pin or roller 61, this roller being free torotate about its axis and to move vertically in the channels 59 and 60.As indicated in FIG. 8, the roller 61 comprises a metal core 62 and aresilient sheath 63 preferably made of a silicone rubber.

Toward the ends of the central compartment 53 are located two rubberbumpers 64 and 65. As shown more clearly in FIG. 11, the bumper 64comprises a block 66 having slightly enlarged section 67 on its upperand lower surfaces and an extension 68 on one face. Bumper 64 is seatedon ledges 69 and 70 formed in internal walls 54 and 55, respectively,with its extension abutting the inside of end wall 19. Bumper 65 ispositioned similarly on ledges 71 and 72 with its extension abutting theend wall 20. It Will be observed from PEG. 6 in particular, that thebumpers 64 and 65 are dimensioned so that the tops of the blocks and theuppermost part of the extensions are above the top of the base. It willalso be noted from FIGS. 5 and 7 that the terminal plates of thecontacts 27, 28, 44 and 48 also extend above the top of the base 10.Further it will be observed that the top (and bottom) of the terminalplates of each of these contacts is provided with a notch 73. In thethree-way switch .depicted in FIGS. l-'7, a bus bar 74 is inserted inthe notches 73 of the movable contact 28 and the blind contact 48. Asexplained below, the cover 12 holds the bus bar 74 in position.

To actuate the switch, the operating lever member 11 is provided. As maybe seen more clearly from FIGS. 1 and 12, in the three-way embodiment,this member com: prises a molded insulation handle 75, an arcuatesection 76 having two stop surfaces "/7 and 78 and a central section ornose 79 extended in a direction opposite to the handle. This section istapered downwardly to a pair of shoulders 80, 89a and terminates in atip 81 which in side elevation is ogival in shape. Extending from eitherside of the lever is a rocker bar 82, i.e. two arcuate surfaces convergesymmetrically and intersect at a line or peak. This has a pie-shapedcross-section with a curved lower surface 83. A short distance in fromeach end of the rocker bar 82 are camming lugs 84 and 85. In thethree-way embodiment shown, these lugs are angularly displaced relativeto each other on the rocker bar 82. The inner surfaces 86, 87 of bothlugs are gently curved from the leading edges 88, 89 to a pointapproximately midway along the inner surface to provide for cammingaction on the contacts. The outer surfaces such as 90 are flat.

As shown in FIGS. 5-7, the operating member 11 is walls 21 and 22 andthe portions of the bar near the I arcuate section 76 of the member 11are seated in arcuate recesses 93, 94 in the internal walls 54 and 55.

The camming lugs 84 and 85 are provided to separate the movable contact28 from the fixed contact 27 against the spring action of the movablecontact while permitting movable contact 44 to remain in contact withblind contact 48; and to separate contacts 44 and 48 whilst permittingcontacts 27 and 28 to remain engaged.

In the position shown in FIGS. 4-7, the camming lug 85 is thrust towardend wall 19. Its rounded inner surface 86 has engaged the bent portionof the movable contact 28, camming that arm inwardly and moving itscontact button 34 away from the contact button 30 on fixed contact 27 Inthis position, the other camming lug 84 is in a position also toward endwall 19, but toward the terminal plate43 of movable contact 44 so thatit permits the contact button of that contact to engage the contactbutton of blind contact 48.

As previously pointed out, the base 10 is closed by a cover 12. Thecover of insulating material is shaped, as by molding, to receive thevarious elements which extend above the base. It is provided, forexample (see FIG. 2) with slots 95 to receive those portions of thecontacts which extend above the level of the base. Studs 96 are providedwhich extend behind the terminal plates of the fixed and movablecontacts to maintain them in proper position. A central aperture 97 isprovided for the handle of operating member 11 and the walls 98 of thisaperture are curved to accommodate the arcuate section 76 of theoperating member. On either side of the aperture 97 are V-shapedrecesses 99 to accommodate the V-shaped upper surface of the rocker bar82. Recesses 100 receive the upper sections of the bumpers 64 and 65. Along transverse recess 101 is provided for bus bar 74.

The operation of the switch will be obvious. In the position shown, themovable contact 28 is held disengaged from fixed contact 27 by camminglug 85, but movable contact 44 is engaged with blind contact 48. Thus, aline connected to terminal screw 36 of movable contact 28 would beconnected via bus bar 74 to blind contact 48 and thence through movablecontact 44 to a line connected to the terminal screw 47 of that contact.Moving the handle of the operating member 11 forward, i.e., toward endwall 19 causes the ogival tip 81 to depress the roller 61 against theaction of spring 59, the spring moving down into tht V-shaped well 56.Once the roller has passed around the end of tip 81, the roller 61 comesto rest on the shoulder a opposite the shoulder it previously contacted.The spring 59 resumes its straight position and the stop surface 77comes to rest against bumper 64. Camming lug has in the meanwhile movedback toward end wall 20 and no longer forces the arm 33 of movablecontact 88 away from fixed contact 27. Thus the spring action of arm 33causes its contact button 34 to engage contact button 30 of the fixedcontact 27. At the same time camming lug 84 has moved toward the endwall 20, forcing the contact button 44a of movable contact 44 away fromthe contact button 48a of blind contact 48 and thus disengaging movablecontact 44 from blind contact 48 and, hence, from movable contact 28.

The embodiment described above illustrates'the invention as used in athree-way switch. Obviously the same structure may also be used as asingle pole switch.

With a few simple alterations, the basic structure may also be convertedto a double pole switch. As shown in FIG. 14, in this embodiment thestructure of the base 110 is identical to the base of the three-wayembodiment except that the movable contact 144, identical with themovable contact 44 of the three-way embodiment, is placed at the window142 where the blind contact 48 is located in the three-way version, anda fixed contact 148, identical with the fixed contact 27 of thethree-way switch. is placed at the window 141.

In place of the operating member 11 used in the threeway version, amember 111 is used. As shown in FIG. 13, the operating member 111 islike member 11 except that camming lugs 184 and 185 are located intransverse alignment on the rocker bar 182.

When the operating member 111 is placed in the base 110, it will beobvious that in one position of the rocker bar both movable contacts 128and 144 will be separated from both fixed contacts 127 and 148, and inthe other position both movable contacts will engage both fixedcontacts.

The double pole structure just described can obviously also be convertedvery easily to a single pole structure.

A consideration of the foregoing description will reveal that thepresent invention provides a simple flexible rugged and economicalstructure which is quiet in operation and readily converted to a varietyof applications. Energy transfer in moving from one position to theother is carried out safely via a simple, flat spring which has a longlife.

The switch contacts open sideways so that any arcing will be clear ofthe walls of the switch, thus to avoid dielectric shorting.

The operating lever with its camming lugs may be made in one piece of awear resistant material such as nylon which needs no lubrication.

A novel feature of the rubber bumpers is that each provides quietstopping of the operating member in two directions, vertically byimpringement of the stopping surface, such as 78, against the top of thebumpers 65 and horizontally by contact of the nose surface against theend of the opposite bumper 64. This multi-directional stopping is incontrast with the unidirectional stopping common heretofore.

The wings such as 21a and 22a of the side walls 21 and 22 provide anadded safety feature by keeping the terminal screws away from the sidesof metal Wall boxes (not shown) in which the switch would normally bemounted. In the three-way version of the switch, the shunt is positivelypressed into connection with the terminal plates by the cover bearingthereon.

Another feature of the present invention of particular interest is theoperating pin or roller 61 which controls the biasing position of theoperating lever. The provision of an elastic sleeve for this rollerresults in a damping effect on its relative energy association with theoperating lever and is responsible to a high degree for the quietness ofoperation of the switch. The fact that the pin is mounted in tracks orchannels guarantees that the pin will retain its desired relationshipwith the operating lever for the life of the switch.

Finally, it may be pointed out that in the construction shown, theoperating lever is positively biased to assume either one position orthe other no matter how the lever is manipulated. This overcomes one ofthe difficulties hitherto experienced in designing quiet switches andenables the present design to meet the rigorous requirements requiredfor Underwriters Laboratory approval.

Modifications within the scope of the invention will occur to thoseskilled in the art. Therefore, the invention is not limited to theprecise forms illustrated and described.

What is claimed is:

1. In an electric switch a hollow insulation casing, fixed and movablecontact means mounted in said casing, an over-center operating memberpivotally mounted in the casing and moving said movable contact meansbetween switch positions for engagement with and disengagement from saidfixed contact means, a leaf spring extending longitudinally of saidcasing and being supported at its ends, a cylindrical anti-frictionroller extending transverse to the leaf spring and engaging themidportion of said leaf spring, said operating member having aconvergently formed inner end portion engaging with said anti-frictionroller, said spring and roller exerting pressure on the opposite sidesof said convergent end portion in different switch positions to bias theoperating member therein, and sound-deadening and energy-absorbingresilient bumpers mounted in said casing adjacent the right and leftsides of said operating member, each bumper having first and secondsurfaces angularly disposed with respect to each other, said operatingmember having first and second surfaces on each of the right and leftsides thereof complementary to and engageable with said first and secondsurfaces of the bumpers, a first surface on the right bumper beingengaged by a first surface on the right side of the operating membersimultaneously with engagement of a second surface on the left bumperbeing engaged with the second surface on the left side of the operatingmember, and vice versa, whereby the two sides of the operating membercome into engagement with two bumpers, in each of said different switchpositions.

2. A switch as claimed in claim 1 in which the said inner end portion ofthe operating member has shoulders on opposite sides of said end portionagainst which said roller rests to assist in positively biasing saidoperating member in said different switch positions.

3. A switch as claimed in claim 1 in which the roller is a rigidcylindrical pin whose ends are located in and guided by slots in saidcasing to maintain a constant positive relationship between the rollerand operating member during the life of the switch, said roller having asleeve thereon of sound-deadening elastomeric material.

4. A switch as claimed in claim 3 in which said sleeve is of siliconerubber.

5. An electric switch for quiet operation as claimed in claim 1 whereinthe movable contact means is formed of a flat flexible metallic stripmounted in said casing edgewise for movement toward and from the planeof movement of the operating member, said operating memher being formedwith camming means engaging with said strip to move the movable contactbetween said different switch positions.

References Cited UNITED STATES PATENTS 2,085,217 6/1937 Hart.

2,669,613 2/ 1954 Despard.

2,807,683 9/1957 Bettencourt.

2,950,366 8/1960 McRoberts et al 200-68 2,969,442 1/ 1961 Benander etal.

1,778,676 10/1930 Kempton 200-166 2,903,531 9/1959 Winter I 200-4662,927,184 3/1960 Hubbell 200-466 ROBERT K. SCHAEFER, Primaly Examiner.D. SMITH, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,354,275 November 21, 1967 Harold E. Schleicher It. is hereby certifiedthat error appears in the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below.

Column 3, lines 66 to 68, strike out i.e. two arcuate surfaces convergesymmetrically and intersect at a line or peak" and insert the same after"shape" in line 65, same column 3; column 5, line 38, for "impringement"read impingement column 6, list of References Cited, add

the following references l ,694 ,928 12/1928 Rider FOREIGN PATENT254,709 8/1956 Great Britain Signed and sealed this 17th day of December1968.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. EDWARD J. BRENNER Attesting Officer Commissionerof Patents

1. IN AN ELECTRIC SWITCH A HOLLOW INSULATION CASING, FIXED AND MOVABLECONTACT MEANS MOUNTED IN SAID CASING, AN OVER-CENTER OPERATING MEMBERPIVOTALLY MOUNTED IN THE CASING AND MOVING SAID MOVABLE CONTACT MEANSBETWEEN SWITCH POSITIONS FOR ENGAGEMENT WITH AND DISENGAGEMENT FROM SAIDCONTACT MEANS, A LEAF SPRING EXTENING LONGITUDINALLY OF SAID CASING ANDBEING SUPPORTED AT ITS ENDS, A CYLINDRICAL ANTI-FRICTION ROLLEREXTENDING TRANVERSE TO THE LEAF SPRING AND ENGAGING THE MIDPORTION OFSAID LEAF SPRING, SAID OPERATING MEMBER HAVING A CONVERGENTLY FORMEDINNER END PORTION ENGAGING WITH SAID ANTI-FRICTION ROLLER, SAID SPRINGAND ROLLER EXERTING PRESSURE ON THE OPPOSITE SIDES OF SAID CONVERGENTEND PORTION IN DIFFERENT SWITCH POSITIONS TO BIAS THE OPERATING MEMBERTHEREIN, AND SOUND-DEADENING AND ENERGY-ABSORBING RESILIENT BUMPERSMOUNTED IN SAID CASING ADJACENT THE "RIGHT" AND "LEFT" SIDES OF SAIDOPERATING MEMBER, EACH BUMPER HAVING FIRST AND SECOND SURFACES ANGULARLYDISPOSED WITH RESPECT TO EACH OTHER, SAID OPERATING MEMBER HAVING FIRSTAND SECOND SURFACES OF THE BUMPERS, AND "LEFT" SIDES THEREOFCOMPLEMENTARY TO AND ENGAGEABLE WITH SAID FIRST AND SECOND SURFACES OFTHE BUMPERS, A FIRST SURFACE ON THE RIGHT BUMBER BEING ENGAGED BY AFIRST SURFACE ON THE RIGHT SIDE OF THE OPERATING MEMBER SIMULTANEOUSLYWITH ENGAGEMENT OF A SECOND SURFACE ON THE LEFT BUMPER BEING ENGAGEDWITH THE SECOND SURFACE ON THE LEFT SIDE OF THE OPERATING MEMBER, ANDVICE VERSA, WHEREBY THE TWO SIDE OF THE OPERATING MEMBER COME INTOENGAGEMENT WITH TWO BUMPERS, IN EACH OF SAID DIFFERENT SWITCH POSITIONS.